/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hbase.zookeeper.client;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.util.LinkedList;
import java.util.List;

import org.apache.hadoop.hbase.zookeeper.client.ClientCnxn.Packet;
import org.apache.hadoop.hbase.zookeeper.client.jute.BinaryInputArchive;
import org.apache.hadoop.hbase.zookeeper.client.proto.ConnectResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * A ClientCnxnSocket does the lower level communication with a socket
 * implementation.
 * 
 * This code has been moved out of ClientCnxn so that a Netty implementation can
 * be provided as an alternative to the NIO socket code.
 * 
 */
abstract class ClientCnxnSocket {
	private static final Log LOG = LogFactory.getLog(ClientCnxnSocket.class);

	protected boolean initialized;

	/**
	 * This buffer is only used to read the length of the incoming message.
	 */
	protected final ByteBuffer lenBuffer = ByteBuffer.allocateDirect(4);

	/**
	 * After the length is read, a new incomingBuffer is allocated in
	 * readLength() to receive the full message.
	 */
	protected ByteBuffer incomingBuffer = lenBuffer;
	protected long sentCount = 0;
	protected long recvCount = 0;
	protected long lastHeard;
	protected long lastSend;
	protected long now;
	protected ClientCnxn.SendThread sendThread;

	/**
	 * The sessionId is only available here for Log and Exception messages.
	 * Otherwise the socket doesn't need to know it.
	 */
	protected long sessionId;

	void introduce(ClientCnxn.SendThread sendThread, long sessionId) {
		this.sendThread = sendThread;
		this.sessionId = sessionId;
	}

	void updateNow() {
		now = System.currentTimeMillis();
	}

	int getIdleRecv() {
		return (int) (now - lastHeard);
	}

	int getIdleSend() {
		return (int) (now - lastSend);
	}

	long getSentCount() {
		return sentCount;
	}

	long getRecvCount() {
		return recvCount;
	}

	void updateLastHeard() {
		this.lastHeard = now;
	}

	void updateLastSend() {
		this.lastSend = now;
	}

	void updateLastSendAndHeard() {
		this.lastSend = now;
		this.lastHeard = now;
	}

	protected void readLength() throws IOException {
		int len = incomingBuffer.getInt();
		if (len < 0 || len >= ClientCnxn.packetLen) {
			throw new IOException("Packet len" + len + " is out of range!");
		}
		incomingBuffer = ByteBuffer.allocate(len);
	}

	void readConnectResult() throws IOException {
		if (LOG.isTraceEnabled()) {
			StringBuilder buf = new StringBuilder("0x[");
			for (byte b : incomingBuffer.array()) {
				buf.append(Integer.toHexString(b) + ",");
			}
			buf.append("]");
			LOG.trace("readConnectResult " + incomingBuffer.remaining() + " " + buf.toString());
		}
		ByteBufferInputStream bbis = new ByteBufferInputStream(incomingBuffer);
		BinaryInputArchive bbia = BinaryInputArchive.getArchive(bbis);
		ConnectResponse conRsp = new ConnectResponse();
		conRsp.deserialize(bbia, "connect");

		// read "is read-only" flag
		boolean isRO = false;
		try {
			isRO = bbia.readBool("readOnly");
		} catch (IOException e) {
			// this is ok -- just a packet from an old server which
			// doesn't contain readOnly field
			LOG.warn("Connected to an old server; r-o mode will be unavailable");
		}

		this.sessionId = conRsp.getSessionId();
		sendThread.onConnected(conRsp.getTimeOut(), this.sessionId, conRsp.getPasswd(), isRO);
	}

	abstract boolean isConnected();

	abstract void connect(InetSocketAddress addr) throws IOException;

	abstract SocketAddress getRemoteSocketAddress();

	abstract SocketAddress getLocalSocketAddress();

	abstract void cleanup();

	abstract void close();

	abstract void wakeupCnxn();

	abstract void enableWrite();

	abstract void enableReadWriteOnly();

	abstract void doTransport(int waitTimeOut, List<Packet> pendingQueue, LinkedList<Packet> outgoingQueue) throws IOException,
			InterruptedException;

	abstract void testableCloseSocket() throws IOException;
}
